SU611288A1 - Differential amplifier - Google Patents

Description

, (54) DIFFERENTIAL AMPLIFIER

input 15 of the amplifier, the load 11 of the connection with the output amplify gsh.

After switching on the input to input 14 or 15, the input signal is given. In the amplification mode, when the signal changes by, for example, the transistor 1 opens, the current is incremented (-37 in the load, which is the current generator of transistor 6, the transistor 3 is closed, in which case the current d3 flows in the load (current generator of transistor 5) of another stage. At the same time, transistor 2 closes, an increase in current (DE) occurs in the load (current generator on transistor 9), and transistor 4 opens, and an increase in current (-t-u 3) in the load (current generator on transistor 1O) occurs. The increment of the current at the input of the current generator on the transistor 6, which is the load on the load of the transistor 1, increases the current increment at its output by the value (2. l3). Since the load of transistor 6 is a differential cascade on transistors 3, 4, the current increment is distributed equally into the emigter circuits of these transistors, and they will open. As a result, the total current increment in the load of transistor 3 is (- "- ДЗ) + (- uD ) 0, and the total current increment in the load of transistor 4 is (+ iv) + (+ l 3) 2 d 3. At the output of the current generator (collector of transistor 5), which is the load of transistor 3, the current does not change, and total current of emitter circuits diff (|) of the potential

the cascade transistors 1, 2 also does not change. There is only a current distribution in the shoulders of this differential cascade. The increment of the current at the input of the current generator on the transistor 9, which is the load of the transistor 2, by the value (-d3 causes the current to increase by the value (2dZ). The current increment at the input of the current generator on the transistor 10, which is the load the value (- "- a DE) causes the current to be incremented at its output by the value (DL). The difference in the output currents of the transistors 9-10 (2d3) determines the current in the total load 11 and the voltage drop across it.

When the input signal exceeds a certain value at which the increment

the current in the load of the differential cascade transistors 1,2, there is a spontaneous switching off of the circuit. In this case, the currents are completely redistributed between transistors 1 and 2 so that transistor 2 is fully closed. With a further increase in the input signal increment (the current in the load of transistor 1 no longer increases, since the current generator of transistor 5 is in the emitter circuit, and transistor 2 is closed. Therefore, the current at the output of the current generator at transistor 6 does not increase. For this reason the transistor 3 starts to curl, the current in its load circuit decreases, and, as a result, the collector currents of transistors 1 and 6 decrease. This leads to an even greater closure of transistor 3, which through the current generator on transistor 5 closes even more transistor 1. An avalanche-like locking of the circuit occurs.

Similarly, the circuit works ari change the signal on С bx The formula of the invention

A differential amplifier containing two differential stages made on transistors of different conductivity types with a current generator in the common emitter circuit of each, while the collector of the transistor of one arm of each differential cascade is connected to the thickness of the power source through an additional current generator whose output is connected to the common load, which differs .em that. in order to increase efficiency, the collector of the transistor of the other arm of each differential of the cascade is connected to the corresponding control source of the signal and to the input of the current generator in the common emitter circuit of the other differential cascade.

Sources of information taken into account in the examination;

1. USSR author's certificate in application number 2022961/09, cl. H 03 F 3/3 1974, on which a positive decision.

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